Jonathan DelCarmen, 19, Andrew Garcia, 18, Alberto Ochoa, 17, and Alejandra Guerrero, 16, are charged with one count each of murder with the special circumstance of murder during an attempted robbery, prosecutors said.

Capital murder charges make Garcia and DelCarmen eligible for the death penalty. Prosecutors will decide later whether to seek that penalty.

Ochoa and Guerrero, who were charged as adults, face life in prison without the possibility of parole, DA's officials said. They are not eligible for the death penalty because they are under 18.

Garcia, Ochoa and Guerrero are also each charged with using a dangerous weapon -- a bat -- to attack Xinran Ji, officials said.

The attack happened July 24 when Ji, an engineering graduate student, was walking home from an off-campus study group about 12:45 a.m. near 29th Street and Orchard Avenue, Los Angeles police said.

Ji was beaten and struck in the head with a bat before he walked back to his apartment in the 1200 block of West 30th Street, leaving a trail of blood, police said.

Ji's roommate found his body about 7 a.m., police said.

After the attack near USC, the suspects allegedly drove to Dockweiler Beach where they allegedly robbed a man and woman. The man managed to escape and flagged down police, officials said.

LAPD Cmdr. Andrew Smith said during a press conference on Monday that the suspects had done "unspeakable things" that "shocked everyone in the department."

Garcia, Ochoa and Guerrero are also charged with second-degree robbery, attempted second-degree robbery and assault with a deadly weapon -- a bat -- in the second incident, DA's officials said.

USC officials said a memorial service was planned for later this week when Ji's parents arrive to the US.

In a statement that was read outside court by a family friend, the victim's parents, Songbo Ji and Jinhui Du, said they are "extremely angry about this horrific act of violence."

"The only thing in our mind is our son. We want to see him. We would be extremely grateful to the U.S. if they can help us to get visas," the man's parents said in the written statement, noting that they have been forced to cancel airline tickets several times because of delays in obtaining their visas.

The victim's parents added that they "do not want to see another incident like this" and said they "hope that USC can enhance security and guarantee the safety of USC students."

Ji's killing marked the second deadly attack on USC graduate students from China in recent years.

Ying Wu and Ming Qu -- who were also engineering students and were both 23 years old -- were shot to death April 11, 2012, as they sat in a double-parked car on a rainy night in the 2700 block of Raymond Avenue, near the USC campus.

One of two men charged in their killings pleaded guilty Feb. 5 to a pair of first-degree murder charges and admitted the special circumstance allegations of murder during the commission of a robbery and multiple murders, along with an allegation of personally using and discharging a firearm.

Bryan Barnes, then 21, was immediately sentenced to life in prison without the possibility of parole, sparing him a potential death sentence. Co-defendant Javier Bolden, 21, is still awaiting trial in connection with the killings.